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Promising results, S83P (related to: timing, idle, vacuum, carb, hesitation)

Discussion in 'Daihatsu Hi jet' started by JMM, Mar 6, 2021.

  1. JMM

    JMM Member

    Long post, but I've got nothing to do today, so:

    I've posted in the past about bogging problems. To address, my mechanic went through everything, installed my new carb, but ended up having to advance timing to >30 degrees BTDC to get the truck to run well. (Here's that post.). It worked, except that over time I kept having to bump up warm idle to avoid hesitation. I finally topped out around 1500RPM.

    This bothered me because that's the wrong way to fix things, and who wants idle that high? (Though it was great for working the dump body when idling.)

    I recently ordered the Pertronix ignitor only to learn that my truck came with (or had been retrofitted with) electronic ignition. (Looks just like this.) I didn't think a February 1991 truck would have this, but OK--no points to mess with. (But my coil is still old--a fresh one is on order.)

    Frustrated about the Pertronix, I started digging through youses' posts and the truck again, because the bizarre advanced timing "fix" bugs me.

    1) I opened the distributor and confirmed vacuum advance is visibly working (to steal another guy's joke: yes I used my mouth and no I won't come over).

    2) Thanks to this post by@ttc I decided to start working through the lines to and from my charcoal canister. He makes a great point that if it's clogged, excess vacuum could be pulling too much fuel into the carb. While he called it a long shot, my hose ends were dry and split, and the ports on the crossmember had a bunch of filth in them. I addressed the lines and blew out the crud with a compressor (Photo #1). I don't know if that 2nd port is supposed to be open like that. Anyone?
    upload_2021-3-6_15-57-35.jpeg

    3) Most of my 25+ year old vacuum delay/check valves are gummed up or just dead (and impossible to find) so I've replaced all I can with generic ones from Amazon (bulky, but they work). Today I saw that I'd missed one going to the carb's enrichment valve (at least that's what I think it is), circled in yellow. I replaced with a new check valve, circled in red.

    upload_2021-3-6_15-59-56.jpeg

    4) At this point, I had nothing to lose, so took her around the block to warm up (started instantly and drove good). Then I disconnected & plugged the vac line to the distributor and was able to dial timing advance back to a pretty normal 10 degrees BTDC, set warm idle to a normal-ish ~950 RPM, and she drove fine. Good pep, no bogging or hesitation, and the exhaust smelled less rich than I've become used to.

    *On my first test drive I forgot to hook the vacuum line back up to the distributor. Might be driver perception, but I felt like the truck was ballsier with the vac advance off. Does that mean anything to anyone? Timing is not my forte.

    30 year old vehicles have gremlins so I'll go out there tomorrow and see if I can get a repeat performance, but so far this is promising.

    A big thank you to this whole forum not just for the tips, but the doggedness to get these quirky little trucks to obey.

    Let's see what I'm saying tomorrow...
     
  2. bobjonah

    bobjonah Active Member

    Your distributor should have two vacuum lines going to it. one is to advance and the other retards it. Is it possible that they were reversed ? Or maybe the advance one was plugged or leaking ? Would explain why you had to mechanically advance your timing so much.
     
  3. JMM

    JMM Member

    @bobjonah, there is only the advance line on my truck. In my test, the ignitor was sprung, so returned to baselie as soon as vacuum was removed. Not sure if that clarifies?

    Given its vintage (1991), I expected points and a condenser, so where there are differences in my truck I'm wondering if they weren't switching over at the factory, or if some fleet mechanic in Japan was just sick of points and swapped in a newer distributor and coil. (I found at least one period Tercel enthusiast site that says the electronic distributor is a direct drop-in.)
     
  4. Koffer

    Koffer Active Member

    The 550cc motors were points and the the 660s got electronic ignition
     
  5. JMM

    JMM Member

    @Koffer, my manual covers several 660cc motors and has instructions for points.

    Edit: my manual is also in terrible engrish so take this with a grain of salt :)
     
    Last edited: Mar 7, 2021
  6. Koffer

    Koffer Active Member

    Mmmm all the JDM units that I’ve seen come thru s80 and 81s with the 550 were points and the s82 , S83p with the 660 were electronic. I know the US off road models used points into the 90s but also had a hold over 550 and older style dashboard
     
    Limestone likes this.
  7. JMM

    JMM Member

    I'm thinking you'd know better than me, because my sample size is "1"
     
  8. Koffer

    Koffer Active Member

    It’s just because I’m a dummy who likes these little trucks and vans .
     
  9. JMM

    JMM Member

    @Koffer , I'm glad you brought this up. I checked my G&R manual for "Daihatsu truck and van models 1990-1998." On page 33 it shows two schematics (one with ECM, one with a distributor with an ignitor). On the backside of the very same page, they show the process of setting points. This could confuse the hell out of someone (like ME!).

    Maybe "ignitor" is their generic term for whatever makes contact in the distributor, but to me "ignitor" meant electronic ignition.

    I hear tales of brave, seafaring men whose eyes have gazed upon Hijet manuals written in English, not translated...
     
  10. Koffer

    Koffer Active Member

    They are justa reprint of the James Danko book and there’s been a few booboos in his book but it’s the only real source in English other then the Japanese manuals . Plus some stuff gets lost a bit in translation
     
  11. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    I think you set the timing with the vacuum advance disconnected. If you tried setting it with the vacuum attached it would have to be set way advanced, (past the marks, advanced) to get it close.

    The timing mark you want to set is the initial advance, set at a low enough rpm, that the mechanical advance isn’t starting to come in yet. And, with the vacuum line pinched or disconnected and blocked.

    You can set the initial timing, with a vacuum gauge connected to the hose which normally goes to the vacuum advance, and setting for maximum vacuum. This assumes you have the idle mixture correctly adjusted. So, you can spend an entire Saturday, tweaking one then the other until you have both right.
     
  12. JMM

    JMM Member

    | So, you can spend an entire Saturday, tweaking one then the other until you have both right.

    LOL
     
  13. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Could be worse. I had a sports car which didn’t have a timing setting. The factory approved method of setting the timing was to do 30 to 60mph acceleration runs in third gear. Where you got the best time was the correct timing. That really did take all Saturday.

    Then dear ol’ dad painted a timing mark on the dampener.
     
    Limestone likes this.
  14. JMM

    JMM Member

    WTH? Was it...British?
     
  15. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    Definitely. With a Lucas Distributor.
     
  16. bobjonah

    bobjonah Active Member

    As well as being credited with the invention of intermittent wipers and self dimming headlamps, LUCAS's groundbreaking research into the smoke theory of electric circuits enabled many rival companies to excell and expand.

    Cheers
     
  17. ed nap

    ed nap Member

    or the Lucas Factory motto: "Put in a good day's work, then home before dark".
    or maybe you've heard this one... "Lucas is an acronym for Loose Unsoldered Connections and Splices".
    or surely you've heard ...Back in the '70s Lucas decided to diversify its product line and began manufacturing vacuum cleaners. It was the only product they offered which didn't suck.


    or better yet... "I've had a Lucas pacemaker for years and have never experienced any prob..."
     
  18. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    My favorite: Why do the British drink their beer warm?

    Lucas builds their refrigerators.
     

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